In the multilayer structure of perovskite solar cells (PSCs), the core is the photoactive layer that absorbs light. The main active material in the photoactive layer is a perovskite thin film, which is prepared from a perovskite material (chemical formula is AMX3, where A and M are two cations with large differences in size, and X is an anion combined with the two). In PSC devices, the structure of the perovskite material used as the photoactive layer is mainly an inorganic-organic hybrid structure. n the single-crystal structure of inorganic-organic hybrid perovskite materials, metal cations and halogen anions form regular octahedral structures, in which organic cations intercalate to balance charges. Such a spatial structure enables perovskite materials to have excellent optical, electrical and magnetic properties. Moreover, by changing the type and quantity of organic molecules and hybrid halogen atoms in the perovskite material, the prepared photoactive layer can obtain higher carrier mobility and lower recombination rate.
Figure 1. Schematic diagram of perovskite CH3NH3PbX3 structural unit
- Perovskite Solar Cell (PSC): PSC has the advantages of high conversion efficiency, low manufacturing cost, and environmental friendliness, which can efficiently convert solar energy into electrical energy, and can also be used to fabricate wearable flexible devices. Therefore, obtaining high-efficiency PSC devices is the key to developing the use of solar energy. After perovskite material absorbs light, it will produce an exciton effect, which can effectively separate holes and electrons, thereby outputting and collecting carriers in a timely manner. Carriers have high mobility and long diffusion lengths in perovskite materials. This enables hybrid perovskite materials with high carrier mobility and low recombination rate. Therefore, the PSC prepared by using the perovskite material as the sensitizing layer has higher photoelectric conversion efficiency and can absorb and convert solar energy to a greater extent.
- Park N G. Organometal perovskite light absorbers toward a 20% efficiency low-cost solid-state mesoscopic solar cell [J]. J. Phys. Chem. Lett., 2013, 4(15), 2423–2429.